Furfural Production from Lignocellulosic Biomass: One-Step and Two-Step Strategies and Techno-Economic Evaluation

Lignocellulosic biomass (LCB) is an abundant renewable energy resource. Hence, the conversion of biomass into fuel and platform chemicals has recently attracted considerable attention. Furfural is an important platform product that can be produced from xylan-rich lignocellulosic biomass. Hemicellulose undergoes two stages, hydrolysis and dehydration, resulting in the production of furfural. In this review, one-step and two-step strategies for furfural production and the subsequent techno-economic evaluation of the integration of furfural and other co-products are presented. The direct one-step production of furfural requires a one-time investment in severe pretreatment conditions or the use of more chemicals, whereas the two-step production requires the separation of additional prehydrolysates, followed by more drastic treatment conditions. In both strategies, water flow, steam flow, organic solvents, deep eutectic solvents (DESs) or ionic liquids (ILs) can be used as solvent phases to hydrolyze hemicellulose. Lewis acid and Brønsted acid catalysts can effectively convert hemicellulose-derived pentose into furfural. A biphasic solvent system can effectively prevent the degradation of furfural in water, thus increasing the yield and selectivity of furfural. The techno-economy assessment results indicate that biorefineries are transitioning to adopting an integrate model of co-production of furfural and other products. Alternative green approaches are increasingly being adopted to make the furfural industry more sustainable and profitable.